The subject matter disclosed herein relates generally to magnetic resonance imaging (MRI) systems, and more particularly to a method and apparatus for imaging a subject using local surface coils.
MRI or Nuclear Magnetic Resonance (NMR) imaging generally provides for the spatial discrimination of resonant interactions between Radio Frequency (RF) waves and nuclei in a magnetic field. Specifically, MRI utilizes hydrogen nuclear spins of the water molecules in the human body, which are polarized by a strong, uniform, static magnetic field of a magnet. This magnetic field is commonly referred to as B0 or the main magnetic field. When a substance, such as human tissue, is subjected to the main magnetic field, the individual magnetic moments of the spins in the tissue attempt to align with the main magnetic field. When excited by an RF wave, the spins precess about the main magnetic field at a characteristic Larmor frequency. A signal, emitted by the excited spins, is received by a conventional RF coil. The output from the RF coil is then utilized to form an image.
To improve the quality of the image, specialized local coils may be utilized, such as to image a certain region or body part. For example, when performing a scan of the lower pelvic region, an endorectal coil or a torso coil maybe utilized. However, conventional endorectal coils provide a limited field of view that may not adequately cover the lower pelvic region. Moreover, conventional endorectal coils are invasive. Accordingly, when the conventional endorectal coil is inserted into the rectum to image, for example, the prostate, this coil may physically move or distort the anatomy to such an extent that the prostate is not in same position during surgery as it is during the MR scan. Additionally, because the conventional torso coil is configured to be placed on the anterior and posterior side of the patient, the Signal-to-Noise Ratio (SNR) is reduced, resulting in a lower quality image.